AGS settings for Outback FM60

SolaRevolution

Re: AGS settings for Outback FM60

I agree with westbranch. Do some longer absorption charging first and avoid excess heating with high EQ voltages on batteries at a low SOC.

It could also be good to get a "baseline" before you start reconditioning and then do it again after your EQ cycles. This could give you an indication of whether or not you are making progress and possibly when you have achieved success.

Without access to take specific gravity readings you should take some "at rest" voltage readings. If you happen to be going out for a few hours in the evening (after sunset) turn everything off at the main DC breakers. When you get back home use a flashlight and check your battery voltages. You may as well check each 6 volt battery's "at rest" voltage while you are at it. This will let you know if all of your batteries are performing similarly.

I didn't catch if your 8 batteries are at 24 volts or at 48 volts. Assuming one string at 48 just put a hand held voltmeter on each battery. If you have parallel strings you should disconnect a paralleling interconnect at the beginning of the rest period then reconnect it only after taking the "at rest" readings.

BTW, testing individual battery voltages under load or during charging can show differences between individual battery performance which is otherwise hard to tell with a sealed bank.

-Alex

BajaSun

Re: AGS settings for Outback FM60

Great advice from everyone - thank you!
Not having sun today I reabsorbed with the genny for 2 hrs and started an EQ until I read the last few posts and stopped it after 20 minutes. During that time I didn't notice any battery heating (from the Mate) and it appeared to be going well. When stopped, I also noticed it holding at a higher voltage than it has been for a little longer, so I'm encouraged, but with only a few amps coming from the sun today it seems a little pointless to try doing much else.

The low battery condition in the mornings has only been for about a week and have been floating by mid-late morning. I will increase absorb time over the next few days, hope for some sun.

Question on bringing the batteries up with the generator and letting the panels finish (assuming there is sun). When I have tried doing this, the CC doesn't keep charging in absorb, it drops to bulk. Is this an incorrect transfer setting? Shouldn't the switch from generator charging to CC charging be smooth and unnoticeable? Lights dim drastically when genny powers down and CC/Inverter kicks in.

Cariboocoot

Re: AGS settings for Outback FM60

BajaSun wrote: »

Question on bringing the batteries up with the generator and letting the panels finish (assuming there is sun). When I have tried doing this, the CC doesn't keep charging in absorb, it drops to bulk. Is this an incorrect transfer setting? Shouldn't the switch from generator charging to CC charging be smooth and unnoticeable? Lights dim drastically when genny powers down and CC/Inverter kicks in.

This is probably a matter of insufficient array size to maintain Absorb Voltage and supply loads. With 400 Amp hours of 24 Volt battery you should have an array of about 1250 Watts, but even so on a less than sunny day it may not be enough to keep the charge Voltage at the Absorb point, especially with load draw. As such the Voltage will fall back and the controller will be in Bulk mode again.

I'd run the gen all the way through at least one complete absorb cycle, even though it is a dreadful use of fuel.

Vic

Re: AGS settings for Outback FM60

Hi Baja,

In general, the heating resulting from EQ is a long slow process. This is mostly seen when the bank is already warm, and/or the EQ is very L-O-N-G and at a high EQ voltage. Am not saying that it should be ignored, but for a moderate time and voltage, EQ should not be a major heating issue. And for AGMs, the EQ voltages are often low compared to Flooded batteries, and therefore less heating.

EQ voltages should be temperature compensated. If the charger does not temp comp the EQ V, then perhaps the battery case temperature be checked from time-to-time, and EQ voltage manually adjusted (reduced) to compesate for the temp rise. Hope that you are using a Battery Temperature Sensor to compensate charge voltages. Believe that the FM-60 and perhaps other OB gizmos (mate?) can tell you the amount of temp compensation that would be applied for the measured batt temps.

If your SGs are behind, then running the genset for an hour or more after the Absorption V is reached is good. And if the PV input has been low for some days, running a complete Abs stage into Float is also a good idea, eventhough is is not the most efficient use of genset fuel.

And if you are running the genset just into the Abs voltage range, and shut it down, it is quite common for the PV to be unable to maintain the charge current necessary to sustain the Abs V, so the CC will immediately drop back to Bulk.

Would recommend that if it has been days since the batteries have seen a completed Absorption stage, that you run the genset to do so.

Good Luck and hope for some sun for you, Vic

inetdog

Re: AGS settings for Outback FM60

Vic wrote: »

If your SGs are behind, then running the genset for an hour or more after the Absorption V is reached is good. And if the PV input has been low for some days, running a complete Abs stage into Float is also a good idea, eventhough is is not the most efficient use of genset fuel.

And if you are running the genset just into the Abs voltage range, and shut it down, it is quite common for the PV to be unable to maintain the charge current necessary to sustain the Abs V, so the CC will immediately drop back to Bulk.

There are some who argue that running the generator for the tail (low current) end of the Absorb is a waste of fuel and that a better approach is to let the generator do the bulk charging before the panel production starts to pick up, and then let the panels carry trough the longer Absorb and into Float. That wastes more PV energy, but perhaps at less cost than the fuel and wear and tear of longer generator hours.

boB

Re: AGS settings for Outback FM60

inetdog wrote: »

There are some who argue that running the generator for the tail (low current) end of the Absorb is a waste of fuel and that a better approach is to let the generator do the bulk charging before the panel production starts to pick up, and then let the panels carry trough the longer Absorb and into Float. That wastes more PV energy, but perhaps at less cost than the fuel and wear and tear of longer generator hours.

This is what I have always been told and it makes sense. One doesn't need to waste the PV energy either but it is cheaper than fuel if it runs things after the generator has been necessary.
You could use diversion to use that excess PV if you have it available.

The system could also be programmed to be smart. i.e. The inverter/charger or whatever is taking the generator and charging the batteries from it could be made
to ramp down periodically during the Absorb cycle to test for available power and then, when ample headroom is available, let the renewables take over the Absorb charge if there is enough time left over.

Just SMOP (Simple Matter Of Programming) except if it suddenly goes from sunshine to full cloudy where the generator would have to re-start to finish the cycle.

boB

Cariboocoot

Re: AGS settings for Outback FM60

inetdog wrote: »

There are some who argue that running the generator for the tail (low current) end of the Absorb is a waste of fuel and that a better approach is to let the generator do the bulk charging before the panel production starts to pick up, and then let the panels carry trough the longer Absorb and into Float. That wastes more PV energy, but perhaps at less cost than the fuel and wear and tear of longer generator hours.

There's no argument; it's true.
You're better off using the gen for Bulk charging and letting the panels finish if you haven't got enough sun to do the whole job.

And if you're really stuck for sunlight you bite the bullet and run the gen for a whole charge cycle right up to Float despite the fuel costs.

Been there, done that, got the functioning system.

BajaSun

Re: AGS settings for Outback FM60

BTW my initial post about settings for AGS has been cleared up. It was a conflict between the FX and FM settings. - Thank you!

However, it did bring to light the battery problem due to having to use the generator.

Just for clarification as I'm getting a in a little over my head. My battery problem is because the absorb setting was too short, correct? Even tho' the batteries did get to float every day, they hadn't been absorbed correctly and have lost their capacity.

So, once I have had the absorb time (2hrs?) every day for a whil (week?) I should attempt an EQ for one hour a day, seven days. It is during this time that I will (hopefully) notice a difference in capacity/efficiency or with the longer absorb times?

IF (I hope not), I end up replacing the batteries (groan), how can I avoid this again? I do have 1,400W array.

HAPPY NEW YEAR!

BB.

Re: AGS settings for Outback FM60

BajaSun wrote: »

Just for clarification as I'm getting a in a little over my head. My battery problem is because the absorb setting was too short, correct? Even tho' the batteries did get to float every day, they hadn't been absorbed correctly and have lost their capacity.

So, once I have had the absorb time (2hrs?) every day for a while (week?)

To be clear the last 10-20% (roughly 80-90% State of charge to "100%" state of charge) recharging your battery takes place during "absorb" voltage. So, most of the time, your battery bank is in "absorb" because you have not discharged below 80% during much of the year. Using the timer (and or end amps) is what triggers the "go to float" transition (which may or may not be related to the actual battery state of charge).

Float is just "storage"/maintaining for the batteries. It does not really do any charging (but does support your system loads directly from the solar array as the charge controller attempts to maintain float voltage).

I should attempt an EQ for one hour a day, seven days. It is during this time that I will (hopefully) notice a difference in capacity/efficiency or with the longer absorb times?

For most of the AGM documentation I have read (which is not much), most AGM "equalization" is simply extended "absorb" times--Not elevated voltage. During winter, if your system is being cycled (home/cabin occupied), you can just set the absorb timer to 4-6 hours (or longer) anyway and just let the sun going down terminate the charging. At least until you are sure the batteries are fully recharged (resting voltage).

IF (I hope not), I end up replacing the batteries (groan), how can I avoid this again? I do have 1,400W array.

Reading about batteries, monitoring voltage, charging current, temperature, etc....

I probably missed it--Do you have some sort of Battery Monitor on your system?

-Bill

Cariboocoot

Re: AGS settings for Outback FM60

Best way to figure your maximum Absorb time is to set it all the way up to 4 hours, run through a charge cycle, and watch the current. At some point during Absorb you will see the current doesn't drop much any more. It will be around 1 to 2 percent of the battery capacity, plus allowance for whatever loads are running from the battery (best to turn off any loads). This is easy to do with an inverter-charger because while it is charging no loads come from the batteries. Whatever amount of time it has taken from the start of Absorb to this low current point, rounded up to the nearest hour, is your maximum Absorb time.

You should definitely run through a full charge cycle like this (with full Absorb) before doing any equalization charge. It is possible the EQ will not be necessary.

BajaSun

Re: AGS settings for Outback FM60

Hi Bill,

No I don't have a Battery Monitor, I refer to the FM or Mate screens.

So I'm actually even more confused now. These batteries (8 ) Lifeline AGM L16 in parallel banks of 24V are about a year old. I've gone to great pains over this year to make sure they float according to the specs ie absorb (yes was only for an hour) at 28.8V, then float at 26.6V

It has only been recently that I noticed "low battery" light on in the mornings, hence the use of generator to help charge as quickly as possible then use the sun. AGM's do charge up remarkably quickly. The only difference in power usage has been a few hours of Xmas tree lights which according to the wattmeter were only 60W. There really are not any other major loads at night except maybe the 1HP water pump kicking in occaisionly.

Today, after absorbing for 2.5 hrs (about all I could take of the generator. Float kicked in but the voltage dropped quite quickly and is maintaining 25.5-7V which is a fully charged bank but not the float voltage even though I can see 5A spare but don't know how many spare from the C40 as it has no screen.

Something is wrong and I'm not sure what - maybe a bad battery or power leaking back up to a bad panel?

Driving me nuts!

Cariboocoot

Re: AGS settings for Outback FM60

In normal operation you'd expect any/all charge sources to be able to maintain Float Voltage (regardless of sufficient Absorb time or not) against loads. If they can't either there's not enough charge power available (as is typical with panels only and a cloudy/short day) or something is drawing more power than the charge sources can produce.

Yes, one bad battery can be the culprit.

Now, how much of a problem is it for you to disconnect all the batteries, let them rest for a few hours, then check the Voltage of each? If one has gone bad it should show up under such a test as being noticeably lower in Voltage than the others (even if they aren't at "ideal" resting Voltage). This will work best if the batteries are fully charged to begin with and can be allowed to sit for quite a long time (overnight for instance) before checking.

And if you check them periodically during their rest you may see signs of rapid Voltage fall-off for some but not others. This is another bad thing.

BB.

Re: AGS settings for Outback FM60

Have you taken an DMM and measured the voltage of each battery? Under all three conditions--rest, load, charge... you are looking for differences. Open/Shorted cell can cause a big issue.

So can a bad wire connection (check current with a DC current clamp meter through each parallel string--Or, pick a common length of wire in each string with a DMM set to 2 volt or 200 mV full scale and measure the voltage drop in each wire--use it as a poor man's current shunt--again looking a battery string that is not sharing current flow during loads/charging correctly).

-Bill

BajaSun

Re: AGS settings for Outback FM60

I have only tested the batteries immediately after charging. I know this is not ideal, but better than nothing. Right now, floating, they read as follows: 6.49, 6.51, 6.74, 6.64, 6.66, 6.75, 6.56, 6.53

inetdog

Re: AGS settings for Outback FM60

BajaSun wrote: »

I have only tested the batteries immediately after charging. I know this is not ideal, but better than nothing. Right now, floating, they read as follows: 6.49, 6.51, 6.74, 6.64, 6.66, 6.75, 6.56, 6.53

6.49 to 6.74 is a bigger variation than I would like to see. I expect that the sum of the voltages for each pair of batteries that make up a series string is identical or very close?

When the two batteries in a series string are differing in voltage, either a long absorb or an Equalization according to the manufacturer's recommendations would be a good idea.

Blackcherry04

Re: AGS settings for Outback FM60

BajaSun wrote: »

I have only tested the batteries immediately after charging. I know this is not ideal, but better than nothing. Right now, floating, they read as follows: 6.49, 6.51, 6.74, 6.64, 6.66, 6.75, 6.56, 6.53

They don't look all that bad, The problem is one square Inch of exposed plate can give those readings, a Classic case of sulfation and diminished Capacity. Time to get to work on them and see what you can salvage. The hard Crystallized Sulfation you'll never get off I don't think.

If I had them, I'd put them in my water tank and do a full charge today and tomorrow I'd start hitting them. I am not real AGM savvy, but a 12V flooded will rise about 6-8 degrees in a hour of EQ measured between the plates depending on the current.

BajaSun

Re: AGS settings for Outback FM60

Those numbers are bottom to top, so right in the middle is the string division. 26.38V for one string, 26.50V for the other. Also in the middle is the charging entrance and the connections to the inverter are at each end - could explain why they increase in voltage towards the middle.

We've been working up to EQ.

Is this enough of a difference to be causing the problems?

BajaSun

Re: AGS settings for Outback FM60

But being AGM's there shouldn't be any exposed plates, per se, correct?

Blackcherry04

Re: AGS settings for Outback FM60

BajaSun wrote: »

But being AGM's there shouldn't be any exposed plates, per se, correct?

Maybe that wasn't the correct term, One square Inch of unsulfated Plate. Thats why voltage is not a good indicator of battery health without knowing the SG, AGM is a guess, but you already know it's a capacity issue. The differences you see is the reason I number my batteries and shuffle them once a year.

You'd do better if you could EQ them in pairs or by themselves.

inetdog

Re: AGS settings for Outback FM60

BajaSun wrote: »

Those numbers are bottom to top, so right in the middle is the string division. 26.38V for one string, 26.50V for the other. Also in the middle is the charging entrance and the connections to the inverter are at each end - could explain why they increase in voltage towards the middle.

We've been working up to EQ.

Is this enough of a difference to be causing the problems?

"The problems", probably not. A problem, yes.
Take a look at this site for tips on how to wire parallel batteries or strings.

westbranch

Re: AGS settings for Outback FM60

Just to reiterate:

What is the max Absorb time for those batteries? If you are not at it, work your way up to that or beyond before EQing.

You need to get to a stable point (V) , at least 3 hours after charging has stopped. Once you are there then cautiously attempt a small EQ 1 HR? Remember the part in that doc about heating.

I do not believe you listed the recommended or max absorb time...
If you can not find one then as Bill said you need to watch what the Amps are just before/when Float starts, it should be somewhere around 10 - 20 Amps for a 1050 Ah battery.
As for voltage, as you are increasing the amount of Absorb time, the end voltage, measured at least 3 hours after charging has stopped and with no loads, should rise and when it stops rising you will have arrived at a good estimate of Absorb time needed.

Hope I made that clear

ps It helps to keep good records of each individual cells readings

And yes recovery is a long process, possibly weeks before you may really know if you have narrowly missed a major disaster

Blackcherry04

Re: AGS settings for Outback FM60

Here is the problem right now, he will hit the Ending Amps now much quicker with them sulfated because he has less plate exposed to the electrolyte. They are in a death spiral. If anything I would lower the EA to stretch the Absorb out as long as he can. This why to do it right you need a Variable Power supply where you can adjust the Voltage and Current. I actually learned this by accident from the Xantrex Service Center. They use these power supplies to test Inverters. I was like wow, I need one, 50 volts and 50 amps with digital read out's.

Vic

Re: AGS settings for Outback FM60

inetdog wrote: »

There are some who argue that running the generator for the tail (low current) end of the Absorb is a waste of fuel and that a better approach is to let the generator do the bulk charging before the panel production starts to pick up, and then let the panels carry trough the longer Absorb and into Float. That wastes more PV energy, but perhaps at less cost than the fuel and wear and tear of longer generator hours.

Hi inetdog,

Yes, very often I am in that camp. HOWEVER, the OP, baja.., has said in many, many ... many posts that there is little sun on a number of days. So, it is often a waste of time and some fuel to start the genset, bulk for a while, shut it off, and watch the battery voltage crash of a low value for the rest of the day, due to the 5% of nominal solar capability.

Seems to me that this bank needs a good long Absorption. And when there is essentially NO SUN, running the genset for hours and hours is a very good thing for what appears to be a chronically undercharged bank. Spend a few pesos on fuel or thousands for a new bank ... perhaps too dramatic a contrast. But, being off-grid, at times have burned more fuel that I wanted to bring my bank back to good SGs. Often, it is difficult to predict tomorrow's weather, and fuel is relatively cheap. I do not want to toss my 8,000 lbs of batteries, to save $10 - 20 in fuel, Just opinions. Vic

inetdog

Re: AGS settings for Outback FM60

Vic wrote: »

Hi inetdog,

Yes, very often I am in that camp. HOWEVER, the OP, baja.., has said in many, many ... many posts that there is little sun on a number of days. So, it is often a waste of time and some fuel to start the genset, bulk for a while, shut it off, and watch the battery voltage crash of a low value for the rest of the day, due to the 5% of nominal solar capability.

Seems to me that this bank needs a good long Absorption. And when there is essentially NO SUN, running the genset for hours and hours is a very good thing for what appears to be a chronically undercharged bank. Spend a few pesos on fuel or thousands for a new bank ... perhaps too dramatic a contrast. But, being off-grid, at times have burned more fuel that I wanted to bring my bank back to good SGs. Often, it is difficult to predict tomorrow's weather, and fuel is relatively cheap. I do not want to toss my 8,000 lbs of batteries, to save $10 - 20 in fuel, Just opinions. Vic

Agreed 100%. But on days when there is sun, running the generator early would probably be better. When there is no sun, you probably also want to run the generator often enough to keep the SOC from dropping below 50% in addition to trying to get a good Absorb charge.

Vic

Re: AGS settings for Outback FM60

inetdog wrote: »

Agreed 100%. But on days when there is sun, running the generator early would probably be better. When there is no sun, you probably also want to run the generator often enough to keep the SOC from dropping below 50% in addition to trying to get a good Absorb charge.

Was really just trying to focus on the topic at hand -- this bank -- which appears chronically undercharged, and the few good sunny days from what I read.

After we get familiar with our systems, most of us seem to develop our own style. But, this style needs to be sensitive to current conditions, and so on. Not trying to argue, but we have buried BajaSun(less) with lots of data and opinions which need digesting. All the Best for the New Year, Vic

BajaSun

Re: AGS settings for Outback FM60

Hi everybody,
It appears that the general opinion is a chronically undercharged battery bank?! Not good news, but glad to know what the problem likely is.

SO, how to deal with it.

Sounds like more absorption time, using the generator if needed (likely). Gradually recondition batteries in this manner until it appears they are acting a little more as expected - could be a few days, could be a few weeks. THEN when settled down, do a conditioning/EQ to set things straight. Likely will be better but will have lost some efficiency, which is a bummer, but is what it is and better than having to purchase a new battery bank after only one years' use of this one.

Assuming this does the job, keep absorb times at max possible (which is a constant conditioning of the AGM's) possibly at the max absorb voltage as suggested by battery manufacturer and before this process, recable batteries to the best balanced situation (in this case two banks of 6V batteries in a 12V figuration x 2 cross wired banks in series for 24V, being sure the inverter and charging circuits are at the same locations) All the time watching temperatures, voltages and current. Do this in the early (morning) stages of charging to allow the sun (if shining) to finish the job.

Phew!

Have I got it? Not sure!

I do know that I have to go put the filets and fresh lobster tails on the grill now for New Years Eve dinner. Hope you all have a great one! Yup, need to digest this (and the lobster) some and I'm SURE will be back with some questions next year!! THANKS for everything so far - LOVE it!

westbranch

Re: AGS settings for Outback FM60

that sounds pretty good...

Enjoy those Filet and lobster dinners. Lamb chops and spuds here.

HNY

vtmaps

Re: AGS settings for Outback FM60

BajaSun wrote: »

It appears that the general opinion is a chronically undercharged battery bank?! Not good news, but glad to know what the problem likely is.
SO, how to deal with it.
<snip>
recable batteries to the best balanced situation (in this case two banks of 6V batteries in a 12V figuration x 2 cross wired banks in series for 24V,

Parallel batteries are problematic and become more so as they age and deteriorate. AGM batteries, because of their lower internal resistance, are even more problematic.
read: http://forum.solar-electric.com/showthread.php?14674

Once the batteries have diverged in their electrical characteristics, you will not be able to properly charge them no matter how you rewire them.
At this point I think you need to disconnect one string and charge the other. If you can get them all to a similar state of charge and capacity (by charging one string at a time), you can try reconnecting them in parallel. Use a current clamp meter to monitor them when they are in parallel.

Some folks use a battery switch so that they can use (or charge) one string at a time.

--vtMaps

BajaSun

Re: AGS settings for Outback FM60

All interesting information - so much knowledge!

I think disconnecting a string and working with them one at a time is an excellent idea. However, I might be hitting my head against a brick wall as I went through the FM logs and the batteries have been down around 23.8 - 24.4 just about every day and that's only a 180 day log, so a year+ of this I would imagine has sadly killed the batteries?. On the other hand the logs show that they have absorbed for at least an hour every day and also floated for a few hours so that would indicate to me that the array is capable of the longer absorb time to keep the banks functional?

Is it possible to adjust the absorb time on a Xantrex C40 as can easily be done with the OB FM60?

BB.

Re: AGS settings for Outback FM60

You have not "killed" the batteries--But you probably have weakend them.

I don't know about the absorb timer on the Xantrex--But you could set FLOAT=ABSORB voltage (or a few tenths volt lower) for now and see what happens.

-Bill